Field of the Disclosure
The present patent application relates to a projection display system, an information processing apparatus, an information processing method, and a storage medium storing instructions for controlling the projection display system.
Description of Related Art
In recent years, a projection display system using a single or a plurality of projection display apparatuses has been permanently installed at large public venues, such as amusement facilities or museum exhibitions, for observation by numerous viewers from a wide range of viewing angles. One issue with such permanently installed projection display systems is the initial installation of the projection display apparatuses and manual adjustment of a projection image shape for maintenance of display images at the time of the initial installation. The manual adjustment requires a great deal of expertise and manpower. In view of this, there has been known a technique to project an adjustment pattern by a projection display apparatus, capture an image of the adjustment pattern by a camera, and produce an adjustment parameter to adjust a projection shape on a screen (Japanese Patent No. 3908255).
According to Japanese Patent No. 3908255, the adjustment pattern is an image of known coordinates indicating sparkle points or crosses aligned at regular intervals or grid patterns. However, it is difficult to detect the coordinates closely on a display plane from such an image.
An image discussed in U.S. Pat. No. 7,907,795 includes a plurality of at least partially overlapping two-dimensional sub-patterns. The two-dimensional sub-patterns are anharmonic (not harmonic) to each other and repeated at different spatial periods.
FIG. 7 is a diagram illustrating images discussed in U.S. Pat. No. 7,907,795. Referring to FIG. 7, first, second, and third sub-patterns 410, 420, and 430 are all overlapped to form an image 440. The image 440 constitutes a part of an image 450 in which images with repetition of the sub-patterns in their respective sizes are overlapped on the entire display screen.
An area of the size covering the first to third sub-patterns is extracted from the image 450 and is analyzed to determine respective two-dimensional offsets for the first to third sub-patterns. The two-dimensional coordinates of the extracted position are determined from the determined two-dimensional offsets.
Accordingly, the coordinates of the image on the projection display apparatus can be specified by projecting an adjustment image for the projection display apparatus and extracting to analyze an arbitrary area of the image captured from a projected image. That is, distortion correction processing for adjusting the shape of the image projected by the projection display apparatus can be performed by projecting the image as illustrated in FIG. 7 with the projection display apparatus and using a captured image obtained by capturing its projection plane.
However, an image projected by the projection display apparatus discussed in U.S. Pat. No. 7,907,795 may be seen on an image captured by a camera at different positions depending on the positional relationship between the projection display apparatus and the camera. That is, using the captured image as it is, and extracting an area without the projected display image for coordinate analysis, for example, would lead to an increase in time for adjustment.